Narrative:

Holding number 1; tower asked us; '[call sign]; are you taking off VFR today?' we replied 'no.' we did not understand the reason for that unusual question; nor did we query the tower controller; nor did the controller elaborate. We were given a vector for takeoff and instructions to stay with tower frequency. After takeoff; tower (or departure control after switching; do not remember which); asked us to verify our squawk. We realize at that point we did not enter a squawk and what tower was covertly implying. We had not done a detailed departure briefing clearance. Fatigue was an issue.while the major fault was not setting a squawk and doing a detailed briefing; tower appeared they were aware of the error. They could have been handled it in a different or more elaborate manner. Also; ground control did not notice us taxiing without a squawk. The ramification was that there was an extra workload in retrieving the squawk and entering it during a higher workload and task saturated environment. Fatigue report submitted.not cutting corners in presenting briefings assuming procedures were done correctly. Understanding how insidious fatigue onset can be. Query controlling agencies as to unusual questions.

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Original NASA ASRS Text

Title: B737 flight crew reported departing with an incorrect squawk code due to fatigue.

Narrative: Holding number 1; Tower asked us; '[Call sign]; are you taking off VFR today?' We replied 'No.' We did not understand the reason for that unusual question; nor did we query the Tower Controller; nor did the Controller elaborate. We were given a vector for takeoff and instructions to stay with Tower frequency. After takeoff; Tower (or Departure Control after switching; do not remember which); asked us to verify our squawk. We realize at that point we did not enter a squawk and what Tower was covertly implying. We had not done a detailed departure briefing clearance. Fatigue was an issue.While the major fault was not setting a squawk and doing a detailed briefing; Tower appeared they were aware of the error. They could have been handled it in a different or more elaborate manner. Also; Ground Control did not notice us taxiing without a squawk. The ramification was that there was an extra workload in retrieving the squawk and entering it during a higher workload and task saturated environment. Fatigue report submitted.Not cutting corners in presenting briefings assuming procedures were done correctly. Understanding how insidious fatigue onset can be. Query Controlling Agencies as to unusual questions.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.